Effect of solution temperature on microstructures and tensile properties of high strength Ti-6Cr-5Mo-5V-4Al alloy

The effect of solution treatment on microstructural characteristics and tensile properties of a new high strength Ti-6Cr-5Mo-5V-4Al alloy was studied. The microstructure-mechanical property relationship is also discussed. The results show that, the Ti-6Cr-5Mo-5V-4Al alloy in solution treated condition has moderate strength levels (800-1000 MPa) with an excellent ductility (-22% of the elongation and 50-60% of the reduction of area). The alloy in the alpha/beta-solution and aged (alpha/beta-STA) condition shows a more attractive combination of strength and ductility than the alloy in the beta-solution and aged condition (beta-STA). The alpha/beta-STA results in the occurrence of mixed a precipitates at nano-scale (-100 nm) and at micron-scale (1 mu m), which contributes to the high ultimate strength levels (1400-1600 MPa). However, the fine beta grains below 10 mu m and the primary alpha phase contribute to good ductility (6-13.5% of the elongation and 22-52% of the reduction of area). The beta-ST leads to equiaxed and coarsen p grains (40-100 mu m), and subsequent aging contributes to the alpha phase with the size of 1-5 mu m. The beta-STA microstructure contributes to 1200-1400 MPa of the ultimate strength with 7-10% of the elongation and 22-28% of the reduction of area, which shows less attractive behavior on the properties than that of the alpha/beta-STA. (C) 2013 Elsevier B.V. All rights reserved.